Seven attackers have been killed after an assault near Kabul's international airport was thwarted, authorities in Afghanistan say.

A Ministry of Interior spokesman, Sediq Sediqi, said two civilians were wounded in Monday's attack that was apparently targeting Nato's airport headquarters. The attackers had rocket-propelled grenades, assault rifles and at least one large bomb.

Deputy Kabul police chief Dawood Amin said there were seven attackers. Two blew themselves up with suicide vests and five were shot and killed by police.

It was unclear if the attack had damaged facilities inside the airport. The attackers had taken over a four- to five- storey building under construction nearby.

The airport was closed to all civilian air traffic during the attack, but subsequently reopened.

Kabul police said in an announcement that attackers wearing suicide vests had occupied one or two buildings under construction on the west side of the airport and were firing at the military facility.

A statement said there was at least one large explosion about 4.30am local time (1am BST) and a gun battle began with security forces.

"It first started with a big explosion which we think was a suicide attack. After that a gun battle started," said a Kabul police spokesman, Hashmat Stanikzai. He said at least five insurgents then occupied two buildings in a single compound and started firing rocket-propelled grenades and automatic weapons.

Explosions could be heard in downtown Kabul, a few miles from the airport. Embassies in the diplomatic zone in the centre of Kabul were quickly locked down and emergency alarms were heard ringing loudly from the British embassy.

"It started just after dawn prayers and I counted about a dozen explosions, mostly RPG fire, coming from the airport," said Emayatullah, who lives next to the airport. Like many Afghans he uses only one name.

The International Assistance Force's joint command said it was aware of reports of an attack, but had no further details.

The US-led Nato coalition's joint command headquarters at the airport runs the day-to-day operations of the nearly 12-year-old war. The airport's military side is also used for Nato transport and other aircraft.